The Berkeley Evolution Site
The Berkeley site offers resources that can help students and teachers learn about and teach evolution. The resources are organized into a variety of learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection states that over time creatures that are more able to adapt to changing environments thrive, and those that are not extinct. Science is concerned with the process of biological evolutionary change.
What is Evolution?
The term "evolution" can be used to refer to a variety of nonscientific meanings. For example it could refer to "progress" and "descent with modifications." Scientifically, it is a term used to describe a change in the characteristics of living organisms (or species) over time. This change is based in biological terms on natural selection and drift.
Evolution is a key concept in modern biology. It is a concept that has been tested and proven through thousands of scientific tests. Contrary to other theories of science, such as the Copernican theory or the germ theory of disease, evolution is not a discussion of religion or God's existence.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a step-like fashion over time. This was called the "Ladder of Nature", or scala Naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833.
Darwin presented his theory of evolution in his book On the Origin of Species published in the early 1800s. It states that all species of organisms have an ancestry that can be traced by fossils and other evidence. This is the modern view on evolution, and is supported by a variety of disciplines which include molecular biology.
Scientists do not know how organisms have evolved, but they are confident that natural selection and genetic drift are the reason for the development of life. Individuals with advantageous traits are more likely to survive and reproduce, and they transmit their genes to the next generation. As time passes the gene pool gradually changes and develops into new species.
Some scientists employ the term evolution in reference to large-scale changes, like the formation of one species from an ancestral one. Certain scientists, including population geneticists, define evolution in a more broad sense by referring to the net change in the frequency of alleles across generations. Both definitions are accurate and acceptable, but some scientists argue that allele-frequency definitions do not include important aspects of evolution.
Origins of Life
The birth of life is an essential step in the process of evolution. This occurs when living systems begin to evolve at a micro-level - within cells, for example.
The origins of life are a topic in many disciplines that include biology, chemistry, and geology. The question of how living things started is of particular importance in science because it is an important challenge to the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
Traditionally, the belief that life can arise from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a common belief before Louis Pasteur's research showed that it was impossible for the emergence of life to be a result of the natural process.
Many scientists still believe that it is possible to make the transition from nonliving substances to living. The conditions needed to create life are difficult to reproduce in a lab. Researchers who are interested in the evolution and origins of life are also eager to learn about the physical characteristics of the early Earth as well as other planets.
Furthermore, the growth of life depends on an intricate sequence of chemical reactions that can't be predicted from the fundamental physical laws alone. This includes the conversion of long information-rich molecules (DNA or RNA) into proteins that perform some function, and the replication of these intricate molecules to produce new DNA or sequences of RNA. These chemical reactions can be compared to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, the protein-based cell machinery, is necessary for the onset life. But, without life, the chemistry that is required to enable it appears to be working.
Abiogenesis research requires collaboration among scientists from various fields. This includes prebiotic scientists, astrobiologists and planet scientists.
에볼루션 바카라 무료 " today is used to describe gradual changes in genetic traits over time. These changes may result from the response to environmental pressures as explained in the article on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This process increases the frequency of genes that confer the advantage of survival for an animal, resulting in an overall change in the appearance of a group. These evolutionary changes are caused by mutations, reshuffling of genes during sexual reproduction and the flow of genes.
While mutation and reshuffling of genes happen in all living organisms, the process by which beneficial mutations are more prevalent is referred to as natural selection. As previously mentioned, those with the beneficial characteristic have a higher reproduction rate than those that do not. This variation in the number of offspring produced over a long period of time can cause a gradual change in the average number of beneficial traits within the group.
One good example is the increase in beak size on different species of finches found on the Galapagos Islands, which have developed different beak shapes to enable them to more easily access food in their new home. These changes in form and shape can also aid in the creation of new species.
Most of the changes that take place are the result of one mutation, but occasionally, multiple mutations occur simultaneously. The majority of these changes could be neutral or even harmful, but a small number could have a positive impact on survival and reproduce with increasing frequency as time passes. Natural selection is a process that could result in the accumulation of change over time that leads to a new species.
Some people mistakenly associate evolution with the concept of soft inheritance that is the belief that inherited traits can be altered by deliberate choice or misuse. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that lead to it. A more accurate description of evolution is that it is a two-step procedure involving the independent and often conflicting forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates - a species of mammals that also includes chimpanzees, gorillas, and bonobos. The earliest human fossils show that our ancestors were bipeds. They were walking on two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In reality, we are most closely connected to chimpanzees belonging to the Pan Genus which includes bonobos and pygmy-chimpanzees. The last common human ancestor as well as chimpanzees lived between 8 and 6 million years ago.
As Suggested Studying has passed humans have developed a number of characteristics, including bipedalism and the use fire. They also developed advanced tools. But it's only in the last 100,000 years or so that most of the important traits that distinguish us from other species have emerged. They include a huge, complex brain and the capacity of humans to build and use tools, and cultural variety.
The process of evolution occurs when genetic changes enable members of an organization to better adapt to their environment. Natural selection is the process that drives this change. Certain traits are preferred over others. The more adaptable are more likely to pass on their genes to the next generation. This is the way that all species evolve and is the foundation of the theory of evolution.
Scientists call it the "law of Natural Selection." The law states that species which have a common ancestor are likely to develop similar traits in the course of time. It is because these traits make it easier to reproduce and survive within their environment.
Every living thing has the DNA molecule, which contains the information needed to guide their growth. The DNA molecule is composed of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases in each strand determines the phenotype, the distinctive appearance and behavior of a person. A variety of changes and reshuffling of genetic material (known as alleles) during reproduction causes variations in a population.
Fossils from the earliest human species Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite some differences in their appearance all support the theory of the origins of modern humans in Africa. Genetic and fossil evidence also suggest that early humans came out of Africa into Asia and then Europe.